Those t shirts, yeah:
"Drop beats not bombs"
"Make love not war"

People buy them all the time, whilst presumably "dropping beats" and "making love" instead of bombs and war. For all their hippy idealism, they have very strong authoritarian tones.
"Make love, NOT war. You better not be making any war over there, or so help me..."

So, my theory: Take one thing you want people to do, then something hippies like doing. You could manipulate the masses whilst also making money.

For example

"Buy these t-shirts, not TRIDENT missle defence system"
"Give me all your money because OXFAM is well brill".

Basically, im a genius.